15317 IUPAC Gold Book - Bunsen coefficient 10.1351/goldbook.15317 15317 current 1 Volume \(V^{\rm{g}}\) of an amount \(n_{\ce{B}}^{\rm{l}}\) of a gas dissolved at a given standard temperature \(T^{^⦵\!}\) (usually \(\pu{273.15 K}\)) and given standard (partial) pressure \(p_{\ce{B}}^{_{^⦵\!}}\) (\(\pu{1 bar} = \pu{0.1 MPa}\) or, in older literature, \(\pu{1 atm}\)) divided by the volume of the solvent \(V^{\rm{l}}\) containing an amount \(n_{\ce{A}}\) of solvent at temperature \(T\) and the given total pressure \(p^{_{^⦵\!}}\). There are two Bunsen coefficients, depending on whether the liquid is the equilibrium solution or the pure liquid, with mathematical definitions:- Bunsen coefficient, solution reference \(\alpha_{\ce{B}} = V^{\rm{g}}(T^{^⦵\!}, p^{_{^⦵\!}}, n_{\ce{B}}^{1})/V^{\rm{l}}(T, p^{_{^⦵\!}}, n_{\ce{A}}, n_{\ce{B}}^{1})\)- Bunsen coefficient, pure solvent reference \(\alpha_{\ce{B}}^{\ast} = V^{\rm{g}}(T^{^⦵\!}, p^{_{^⦵\!}}, n_{\ce{B}}^{1})/V^{\rm{l}}(T, p^{_{^⦵\!}}, n_{\ce{A}})\)where \(n_{\ce{B}}^{\rm{l}}\) is the amount of dissolved gas in the liquid solution. The relations between the molality \(m_{\ce{B}}(p^{_{^⦵\!}})\) or mole fraction \(x_{\ce{B}}(p^{_{^⦵\!}})\) of dissolved gas and the Bunsen coefficients are \[\begin{array}{l} \frac{1}{x_{\ce{B}}(p^{_{^⦵\!}})} = 1 + \frac{1}{m_{\ce{B}}(p^{_{^⦵\!}})M_{\ce{A}}} = 1 + \frac{RT^{^⦵\!}Z_{\ce{B}}^{^⦵\!}(T^{^⦵\!})}{p^{_{^⦵\!}}V_{\ce{A}}\alpha_{\ce{B}}} \\ \frac{1}{x_{\ce{B}}(p^{_{^⦵\!}})} = 1 + \frac{1}{m_{\ce{B}}(p^{_{^⦵\!}})M_{\ce{A}}} = 1 + \frac{RT^{^⦵\!}Z_{\ce{B}}^{^⦵\!}(T^{^⦵\!})}{p^{_{^⦵\!}}V_{m,\ce{A}}\alpha_{\ce{B}}} \end{array}\] where \(V_{\ce{A}}\), \(V_{m,{\ce{A}}}\) are the respective partial molar volume and molar volume of the solvent and \(Z_{\ce{B}}\) is the compression factor of the gas. The Bunsen coefficient and the related quantities for expression of gas solubility; absorption coefficient, Kuenen coefficient, and Ostwald coefficient appear frequently in the older literature of gas solubility determination. However, the modern practice, recommended here, is to express gas solubility as molality, mole fraction, or mole ratio. Kuenen coefficient https://goldbook.iupac.org//terms/view/15374 Ostwald coefficient https://goldbook.iupac.org//terms/view/15377 mole fraction https://goldbook.iupac.org//terms/view/15376 mole ratio https://goldbook.iupac.org//terms/view/15341 PAC, 2008, 80, 233. 'Glossary of terms related to solubility (IUPAC Recommendations 2008)' on page 239 (https://doi.org/10.1351/pac200880020233) https://goldbook.iupac.org/terms/view/15317/html https://goldbook.iupac.org/terms/view/15317/json https://goldbook.iupac.org/terms/view/15317/plain Citation: 'Bunsen coefficient' in IUPAC Compendium of Chemical Terminology, 5th ed. International Union of Pure and Applied Chemistry; 2025. Online version 5.0.0, 2025. 10.1351/goldbook.15317 The IUPAC Gold Book is licensed under Creative Commons Attribution-ShareAlike CC BY-SA 4.0 International (https://creativecommons.org/licenses/by-sa/4.0/) for individual terms. If you are interested in licensing the Gold Book for commercial use, please contact the IUPAC Executive Director at executivedirector@iupac.org . The International Union of Pure and Applied Chemistry (IUPAC) is continuously reviewing and, where needed, updating terms in the Compendium of Chemical Terminology (the IUPAC Gold Book). Users of these terms are encouraged to include the version of a term with its use and to check regularly for updates to term definitions that you are using. 2026-07-27T20:15:26+00:00